1. Field of the Invention
This invention relates to maleic anhydride polymers, and, more particularly, to new and improved terpolymers of maleic acid, maleic anhydride and an alkylvinylether.
2. Description of the Prior Art
Maleic anhydride polymers, and copolymers with alkylvinylethers are well known in the art. However, terpolymers of maleic anhydride, maleic acid and alkylvinylethers are difficult to make, particularly terpolymers, which are suitable for use in personal care products.
Accordingly, it is an object of this invention to provide new and improved terpolymers of maleic anhydride, maleic acid and alkylvinylethers.
What is described herein is a terpolymer of maleic acid (MAA)/maleic anhydride (MAN)/alkylvinylether (AVE), e.g. methylvinylether, preferably solvent-free, and preferably having a composition, in mole %, of MAA 1-49%, MAN 1-49% and AVE 50%; made by partial cyclization, e.g. 1-99%, of a maleic acid/alkylvinylether copolymer; suitably, by heating at 50-150xc2x0 C. preferably at 60-135xc2x0 C., for a predetermined period of time, and under suitable reaction conditions.
Subsequent reaction of the terpolymer with alcohols/amines forms ester/amides, e.g. the menthol half-ester of the terpolymer.
The terpolymer also may be derivatized to form amides and imides, as described by Ulmer, H., in U.S. Pat. Nos. 5,869,695; 5,886,194; 5,959,122; 5,994,385; 6,025,501; described derivatized polymers of maleic anhydride, including esters/amides/imides.
The terpolymer in powder form may be used as a bioadhesive having a defined hydrophilic/hydrophobic ratio, preferably including a stabilizer to increase its molecular weight. The terpolymer also is suitable in oral care, pharma and personal care compositions, which are advantageously solvent free.
The terpolymer of the invention is made by partial (1-99%) cyclization of maleic acid/alkylvinylether copolymer, as follows: 